Metabolism and Enzymes
We tend to associate individuals with a high metabolism with being active and those with a slow metabolism as being lazy and heavy. Metabolism is our body's way of gaining energy through chemical reactions that converts our food intake into the energy that we require to do our daily activities. Almost every process in our body is dependent upon energy and hence it is vital to our living. The food that we eat has calories which are then converted into energy by the aid of enzymes. Enzymes speed up these chemical reactions by lowering the activation energy. Since proteins lose their function at high temperatures, enzymes are crucial. Without these catalysts, these reactions would not be able to occur. Enzymes have a unique shape that allows them to bond with a reactant called a substrate. Upon the formation of this bond, a chemical reaction occurs and upon completion, the enzyme is recycled to catalyze another reaction.
Photosynthesis
Plants are similar in the sense that they are also active in this process. This process is called photosynthesis. It is a chemical process that converts the sun's energy into chemical energy which is captured by chloroplasts within the plant and produces molecules such as glucose. You will learn more about it in the next section.